QGIS/python/plugins/processing/algs/qgis/SimplifyGeometries.py

111 lines
4.4 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
SimplifyGeometries.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from qgis.PyQt.QtGui import QIcon
from qgis.core import Qgis, QgsFeature, QgsGeometry, QgsWkbTypes, QgsMapToPixelSimplifier
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.ProcessingLog import ProcessingLog
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterSelection
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class SimplifyGeometries(GeoAlgorithm):
INPUT = 'INPUT'
TOLERANCE = 'TOLERANCE'
OUTPUT = 'OUTPUT'
METHOD = 'METHOD'
def getIcon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'simplify.png'))
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Simplify geometries')
self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
self.addParameter(ParameterVector(self.INPUT,
self.tr('Input layer'),
[dataobjects.TYPE_VECTOR_POLYGON, dataobjects.TYPE_VECTOR_LINE]))
self.methods = [self.tr('Distance (Douglas-Peucker)'),
'Snap to grid',
'Area (Visvalingam)']
self.addParameter(ParameterSelection(
self.METHOD,
self.tr('Simplification method'),
self.methods, default=0))
self.addParameter(ParameterNumber(self.TOLERANCE,
self.tr('Tolerance'), 0.0, 10000000.0, 1.0))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Simplified')))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
tolerance = self.getParameterValue(self.TOLERANCE)
method = self.getParameterValue(self.METHOD)
pointsBefore = 0
pointsAfter = 0
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
layer.fields().toList(), layer.wkbType(), layer.crs())
features = vector.features(layer)
total = 100.0 / len(features)
if method != 0:
simplifier = QgsMapToPixelSimplifier(QgsMapToPixelSimplifier.SimplifyGeometry, tolerance, method)
for current, input_feature in enumerate(features):
out_feature = input_feature
if input_feature.geometry():
input_geometry = input_feature.geometry()
pointsBefore += input_geometry.geometry().nCoordinates()
if method == 0: # distance
output_geometry = input_geometry.simplify(tolerance)
else:
output_geometry = simplifier.simplify(input_geometry)
pointsAfter += output_geometry.geometry().nCoordinates()
out_feature.setGeometry(output_geometry)
writer.addFeature(out_feature)
progress.setPercentage(int(current * total))
del writer
ProcessingLog.addToLog(ProcessingLog.LOG_INFO,
self.tr('Simplify: Input geometries have been simplified from %s to %s points' % (pointsBefore, pointsAfter)))